Some types of tobacco such as bright leaf or flue-cured tobacco are harvested by removing selected individual leaves from tobacco plants growing in a tobacco field. Typically the individual tobacco leaves are placed in a container component after removal from the tobacco plant where they are collected in bulk for transfer to a drying and curing facility for further processing.
Traditionally tobacco leaves were harvested manually and prepared for curing by manually tying the individual tobacco leaves in groups or hands comprising three to eight leaves. Each hand was then typically supported by tying the butt ends of the leaves of the hand together with a string and supporting successive interconnected hands on an elongated stick. A plurality of such sticks with the groups of leaves supported thereon were placed in a curing barn so that the leaves were exposed to curing air with the barn.
This traditional stick barn method of curing tobacco was slow and labor intensive. A method and apparatus for bulk curing whole leaf, flue-cured tobacco was described in U.S. Pat. No. 3,105,713 issued Oct. 1, 1963 and U.S. Pat. No. 3,110,326 issued Nov. 12, 1963 to F. J. Hassler, which patents are hereby incorporated into the present application in their entirety. These references disclose a tobacco curing rack and method of aligning tobacco leaves therein so that the racked leaves are essentially parallel, the tobacco stalks are pointing in the same general direction and the leaves form a single tier which is approximately one leaf length high. This single tier type of bulk curing rack is sometimes referred to as a conventional bulk curing rack and, although it represents an improvement over the traditional stick barn method, this type of curing rack has a relatively small leaf capacity and is relatively difficult to fill with leaves because the leaves must be carefully aligned and generally parallel within these conventional curing racks.
In the middle of 1970s a box-type tobacco curing rack came into existence which does not require the whole leaf tobacco to be arranged into single tiers. Tobacco leaves instead are arranged therein with the leaves generally open and flat, the leave surfaces generally parallel and the leaves uniformly distributed therein. When tobacco leaves are placed in a box-type rack, they are typically placed therein with their leaf surfaces parallel to the ground and when the box type rack is full of leaves, a cover is placed thereover and the rack is placed in a curing barn such that the leaf surfaces are generally vertical. Then, heated and conditioned air is forced through the leaves to cure the same. Accordingly, box-type tobacco racks, also referred to as tobacco curing bins, are typically large, generally rectangular boxes which operate in two general orientations: 1) an open, generally horizontal orientation in which the rack is filled with leaves and 2) a closed, generally vertical orientation which supports the leaves therein in proper position for curing and drying.
It is well-known that uniform distribution of the tobacco leaves within a curing bin is essential in bulk curing of tobacco. The individual tobacco leaves must be loaded compactly in a curing bin without voids so that during bulk curing, the heated and conditioned air that is forced between the leaves will flow uniformly therethrough without the air flow concentrating within voids. The advent of these box-type tobacco curing bins in the 1970's presented an opportunity to significantly automate the handling of tobacco from tobacco harvesting through processing and to reduce the manual labor traditionally associated therewith because these bins made it possible to prepare large numbers of leaves for the curing barn at one time. Mechanical harvesting of tobacco leaves was well known in the 1970's which permitted the initial harvesting of leaves from the field in bulk.
Mechanical harvesting of individual whole tobacco leaves was in use in the 1960s which reduced the need to manually harvest tobacco leaves. Typically tobacco leaf harvesting on large farms is performed by a specialized tobacco combine or, on smaller farms, with a mechanical tobacco harvesting implement attached to a conventional tractor. A tobacco combine is typically comprised of a plurality of mechanical power driven defoliating units which remove a swath or preselected series of leaves from each plant in at least one row of tobacco at a time as the combine moves along the rows. Often the preselected leaves are removed from the bottom of each plant as the leaves become mature during the growing season. Examples of combines including single row and double row combines are found in U.S. Pat. No. 3,772,862 issued Nov. 20, 1973 to Robert W. Wilson; U.S. Pat. No. 4,178,745 issued Dec. 18, 1979 to Robert W. Wilson; and U.S. Pat. No. 4,476,669 issued Oct. 16, 1984 to Robert W. Wilson, which patents are hereby incorporated by reference into the present application in their entirety.
As described fully in the incorporated patent references '862,'745, U.S. Pat. No. 4,476,669, the defoliator units strip leaves from the plants and delivers the same to a plurality of conveyor assemblies which cooperate to move the leaves upwardly and rearwardly above an elevated platform on the combine on which a suitable leaf collection receptacle is mounted. Upwardly extending sections of a conveyor assembly discharge the leaves into the leaf receptacle. The conveyor assembly frequently deposits the leaves directly in the receptacle as an amorphous mass. The leaves are therefore randomly arranged, the leaf surfaces are not parallel and the leaves are not uniformly packed or uniformly distributed within the receptacle. Leaves at the bottom of the receptacle are subject to the accumulated weight of the leaves in overlying relation therewith within the receptacle and, because the receptacle is supported on a moving vehicle, the dynamic forces on the overlying leaf mass may compress or pack the leaves at the bottom of the leaf collection receptacle somewhat. Contemporary mechanical combines are capable of harvesting large masses of leaves in a short period of time. Some mechanical harvesters typically harvest 4,000 to 8,000 pounds of tobacco leaves per hour.
This mechanization has reduced tobacco harvesting labor costs but has created the problem of how to transfer the large amorphous mass of tobacco leaves from the leaf collection receptacle on the combine to tobacco curing bins or tobacco racks for further tobacco processing. Stated another way, it can be appreciated that the tobacco combine and various dedicated harvesting implements for conventional tractors have enabled tobacco farmers to quickly harvest large quantities of leaves with relatively little labor; large capacity curing bins provide a way to economically transfer large quantities of tobacco leaves to the curing barn. A persistent problem facing tobacco farmers, however, is how to transfer quickly and with relatively few workers large quantities of amorphous masses of tobacco leaves gathered in the tobacco field to the large capacity curing bins.
One solution to this problem is to distribute the harvested leaves directly into a curing bin or rack that is mounted on the combine. An example for the former approach is illustrated in the above incorporated '745 United States reference. This approach offers many advantages. For example, the '745 reference discloses a method and apparatus for mechanically distributing tobacco leaves directly into a curing bin without additional manual labor. This reduces labor costs and enables the tobacco grower to send the leaves directly from the combine to the curing barn.
It may be desirable, however, to collect the harvested leaves in a separate collection receptacle in a first step and then transfer them to a curing bin or rack in a second step. One reason may be weight. Very large curing bins are in use, an example of which is disclosed in U.S. Pat. No. 4,136,465 issued Jan. 30, 1979 to Robert W. Wilson which patent is hereby incorporated by reference into the present application in its entirety. The curing bin in the '465 reference is also a section of the curing barn; it may be advantageous to fill this size curing bin in a second step as opposed to filling it directly on the combine in a manner described, for example, in the '745 reference. Were such a large curing bin to be mounted on a combine, this may result in undesirable combine wheel load, particularly if the ground is wet or the soil is soft.
It may also be desirable to combine tobacco leaves from different sources in one curing bin or rack for curing. Tobacco growers with small acreage, for example, may not harvest leaves with a combine. The leaves may be delivered for drying and curing in sheets. These so-called "sheeted leaves" are typically hand picked and placed on a sheet which is folded thereabout and tied for transport. It may be desirable to use a separate second step to fill the tobacco curing bins to accommodate tobacco from a plurality of sources.
Consequently, a need exist for a method and assembly for transferring a large amorphous mass of harvested tobacco leaves to a curing rack or curing bin for drying and curing.